Sports Medicine Research: In the Lab & In the Field: PNF Stretching Increases Ankle Dorsiflexion Range of Motion and Decreases Tendon Stiffness Following a 6 Week Program (Sports Med Res)
Wednesday, May 7, 2014

PNF Stretching Increases Ankle Dorsiflexion Range of Motion and Decreases Tendon Stiffness Following a 6 Week Program

Effect of PNF stretching training on the properties of human muscle and tendon structures.

Konrad A, Gad M, and Tilp M. Scand J Med Sci Sports. 2014 [epub ahead of print].

Take Home Message: Following a 6 week proprioceptive neuromuscular facilitation stretching program ankle dorsiflexion was increased and tendon stiffness decreased.

Despite the common use of proprioceptive neuromuscular facilitation (PNF) stretching we have limited information about how it affects range of motion, maximal isometric torque, passive resistive torque, muscle stiffness or tendon stiffness. By better understanding the effect of PNF stretching on musculotendinous performance and structure, clinicians may be able to optimize rehabilitation and pre-participation warm-ups to minimize injury without inhibiting performance. Therefore, Konrad, Gad, and Tilp completed a randomized trial to analyze the effects of a 6-week PNF stretching program on the functional and structural parameter of the ankle joint compared with individuals assigned to a control group. Researchers randomly assigned 49 police cadets (31 male, 18 female) to either a PNF stretching group (25 cadets) or control group (24 cadets). Prior to any intervention, participants’ range of motion (ROM), passive resistive torque, maximum voluntary contraction, and parameters of the muscle and tendon structure (for example, fascicle length, pennation angle, tendon stiffness) were measured. Participants in the PNF group performed a PNF stretching program 5 times per week over a 6 week period. The stretching program consisted of a standing wall stretch of the plantar flexors for 15 seconds, followed by an isometric contraction of the plantar flexors for 6 seconds, and then contract the dorsiflexor muscles for another 15 seconds. This cycle was repeated four times per session. Following the 6-period, the control group had not noticeable changes but the cadets who performed PNF stretching had greater ankle dorsiflexion ROM and pennation angle at rest as well as less active and passive tendon stiffness. Fascicle length, pennation angle in stretching position, passive resistance torque, and maximum voluntary contraction torque did not change among cadets in either group.

Overall, the present study supports the use of PNF stretching as an effective method of increasing dorsiflexion range of motion. Also interesting is the finding that while ankle dorsiflexion increased, the authors only observed changes in the tendon stiffness and pennation angle at rest. This is interesting as it may indicate that while the ROM increases, the muscle may maintain many of its characteristics needed for optimal performance. To better understand the relationship between PNF stretching and its benefits to physical performance, future studies should compare PNF stretching to static and ballistic stretching, as well as measure a more sport-specific movements. Ultimately, this study should aid encourage clinicians in incorporating more PNF stretching into their rehabilitation and conditioning programs.

Questions for Discussion: How often do you prescribe PNF stretching in your rehabilitation or conditioning programs? Have you found PNF stretching to be particularly beneficial to ROM and or overall performance?

Written by: Kyle Harris
Reviewed by: Jeffrey Driban

Related Posts:
Acute Effects of Static and Dynamic Stretching on Kicking Mechanics

Konrad, A., Gad, M., & Tilp, M. (2014). Effect of PNF stretching training on the properties of human muscle and tendon structures Scandinavian Journal of Medicine & Science in Sports DOI: 10.1111/sms.12228

4 comments:

Alexander Dailey said...

This article certainly reinforces the clinical meaningfulness of PNF stretching. For those in the DI setting, the utilization of PNF stretching coupled with other techniques make it a beneficial tool to use. I utilize the combination of joint mobilization (from toes to the fibular head), PNF stretching, and PNF strengthening (slow reversal or agonist reversal done two to three times per week). The joint mobilization and PNF stretching typically occurs four to five times per week to help improve range of motion as part of rehabilitation or prevention purposes. During the last year of my clinical rotation, I utilized the combination of techniques in runners (both distance and sprinters) in the DI setting. The combination of techniques (even if PNF is the only treatment done due to time constraints) has helped in both range of motion and overall performance. The feasibility of the combination of treatments also makes it practical for the DI setting, in which treatment is done in ten minutes. Athletes respect the hands-on approach and adhere to the rehabilitation as a result.

Kyle said...

Alexander,

Great comment! Thank you. I think your utilization of PNF techniques highlights how versatile this PNF is in clinical practice. Specific to your comment, you mentioned you utilized these techniques in a clinical rotation. Would you say that during this rotation your clinical supervisors were also utilizing and/or teaching these techniques? With such a effective training technique I am interested in how much emphasis clinical educators are placing on it.

Adam E said...

This study further validates the importance of utilizing PNF stretching, but I am very curious as to how it compares to static and ballistic stretching. What type of program was the control group using in this study, if not static or ballistic? With an in depth comparison between the different techniques, I think enhancements could be made in the way we approach warming up as well as rehabilitation. While there continues to be positive feedback on PNF, I have yet to see it implemented across the board and feel that it probably needs to be if the advantages are great.

Jeffrey Driban said...

Adam: Thanks for the comment! You may be interested in these posts that used PNF and other types of stretching...
http://www.sportsmedres.org/2014/09/acute-gains-in-motion-after-single-bout.html
http://www.sportsmedres.org/2011/11/acute-effects-of-different-stretching.html
The control group continued their normal training in this study. I think the reason static and dynamic stretches are still more common than PNF is their simplicity. Granted that's not an excuse and it may be helpful to have not only more clinical trials showing the efficacy of PNF stretching relative to other stretching programs but also having more people showing how to perform PNF stretching, especially using techniques a patient can do on their own. Thanks!

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